Hexagonal perovskite related oxide ion conductor Ba 3 NbMoO 8.5 : phase transition, temperature evolution of the local structure and properties

DOI: 10.1039/C9TA08378B

Authors: Matthew S. Chambers (Durham University; Diamond Light Source) , Kirstie S. Mccombie (University of Aberdeen) , Josie E. Auckett (Durham University) , Abbie C. Mclaughlin (University of Aberdeen) , John T. S. Irvine (University of St Andrews) , Philip A. Chater (Diamond Light Source) , John S. O. Evans (Durham University) , Ivana Radosavljevic Evans (Durham University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Materials Chemistry A , VOL 116

State: Published (Approved)
Published: October 2019
Diamond Proposal Number(s): 19729

Abstract: Ba3NbMoO8.5 has recently been demonstrated to exhibit competitive oxide ion conductivity and to be stable under reducing conditions, making it an excellent potential electrolyte for solid oxide fuel cells. We report here the first investigation of the local structure in Ba3NbMoO8.5, carried out using variable-temperature neutron total scattering and pair distribution function (PDF) analysis. This work reveals a significant degree of disorder in the material, even at ambient conditions, in both the cation and the anion arrangements and suggests the prevalence of the five-fold Nb/Mo coordination. In addition, high resolution powder X-ray diffraction data indicate that the temperature-dependent structural changes in Ba3NbMoO8.5 are due to a first order phase transition, and reveal a previously unreported effect of thermal history on the room-temperature form of the material. PDF modelling shows that Ba3NbMoO8.5 has an essentially continuous oxygen distribution in the ab plane at 600 °C which leads to its high oxide-ion conductivity.

Diamond Keywords: Semiconductors

Subject Areas: Chemistry, Materials


Instruments: I11-High Resolution Powder Diffraction

Added On: 07/11/2019 14:22

Discipline Tags:

Physical Chemistry Chemistry Materials Science Perovskites Metallurgy

Technical Tags:

Diffraction X-ray Powder Diffraction